This invention is concerned with a new strain of Escherichia coli which is enteropathogenic to both calves and piglets, and to a colibacillosis vaccine prepared therefrom.
Colibacillosis, commonly called (white) scours, is an enteric disease of which diarrhea is the major symptom and is caused by strains of E. coli pathogenic to a particular species of animal. The species specificity is determined by the type of pilus attachment factor elaborated by the infecting E. coli. Strains pathogenic to calves share a common pilus antigen, K99, while three different pilus antigens, K88, K99 and 987, are associated with pathogenicity in piglets. Thus a vaccine containing only K99 pili would be species specific for calves, while any vaccine containing only one type of pilus could not be fully protective in piglets. A vaccine that was not species specific would require a combination of cellular material from at least two organisms. Combination vaccines are known but they have several disadvantages such as large manufacturing volumes, large doses, and the questionable practice of introducing to the host non-efficacious bacterial antigens.
Now, with the present invention there is provided a new strain of Escherichia coli that is enteropathogenic to both calves and piglets and useful for preparation of a polyvalent bacterial colibacillosis vaccine to prevent colibacillosis caused by either K88.sup.+ or K99.sup.+ E. coli.
There is also provided by this invention a process for preparing the new strain of E. coli by bacterial conjugation.
There is further provided a monovalent colibacillosis vaccine prepared from one strain of E. coli for use in both calves and piglets and a method of prophylactic treatment of colibacillosis in calves and piglets, with the new vaccine.